Jaw-operating mechanism for chucks.



A. E. CHURCH.

JAW OPERATING MECHANISM FOR CHUCKS.

APPLICATION FILED DEC-21.1914.

Patented May 2, 1916.

4 SHEETS-SHEET I.

Tm: COLUMBIA ILANOGRMH 00.. WASHINGTON. u. c

. A.E.CHIIRCH.

.IAW OPERATING MECHANISM FOR CHUCKS.

APPLICATION FILED DEC. 2!. 1914.

Patented May 2, 1916.

4 SHEETS-SHEET 2.

A. E. CHURCH.

JAW OPERATING MECHANISM FOR CHUCKS.

APPLICATION FILED DEC. 21. l9l4- 1916. 4 SHEETS-SHEET 3.

t n e 5311 us wh THE COLUMBIA PLANOGRAPH c0, WASHINGTON, D. C

A. E. CHURCH.

.IAW OPERATING MECHANISM FOR CHUCKS. APPLICATION FILED DEC.21, I914.

L1 1 ,M. Patented May 2,1916.

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Witmeooan ALBERT E. CHURCH, OF NEW BRITAIN, CONNECTICUT.

JAIN-OPERATING MECHANISM FOR CHUCKS.

Specification of Letters Patent.

Patented May 2, 1918.

Application filed December 21, 1914. Serial No. 878,321.

To all whom it may concern.

Be it known that I, ALBERT E. CHURCH, a. citizen of the United States, residing at New Britain, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Jaw-Operating Mechanisms for Chucks. and I do declare the following to be a full, clear, and

exact description of theinvention, such as.

as to automatically cause the jaws to take a firm grip should any slipping or loosening thereof occur for any reason.

Another object is to provide cushioned jaw operating means to prevent the jaws from crushing or otherwise injuring the article gripped thereby and yet securely hold .it for turning with the chuck.

With these and other objects in view, the invention consists of certain'novel features of construction and the combination and arrangement of parts as will be hereinafter more fully described and claimed.

In the accompanying drawings: Figure 1 represents a plan view of a chuck equipped with this improvement; Fig. 2 is a horizontal section thereof with parts broken 7 out showing the position of the members hefore the jaws are brought into gripping engagement with the article to be held; Fig. 3 is a similar view showing the jaws in engagement with the article and prior to the tighteningthereof; Fig. 4is a similar view showing the jaWs in clamped position and the cushioning spring compressed; Fig. 5 is an enlarged horizontal section showing this improvement with the parts in position forreleasing the jaws; Fig. 6 is a vertical longitudinal section taken on the line 66 of Fig. 5; Fig. 7 is a transverse section taken on the line 7-7 of Fig. 5; Fig. 8 is a similar view taken on the line 88 of Fig. 5; Fig. 9 is a similar view taken on the line 9-9 of Fig. 5; Fig. 10 is a front elevation partly in section; Fig. 11 is a transverse section taken substantially on the line 11-11 of Fig. 4.

In the embodiment illustrated a chuck head 1 is shown having the usual hollow driving spindle 2 attached thereto by screws or bolts 3 passing through a faceplate 2 and engaging said head which latter is hollow to provide a chamber for a purpose to be described. (See Figs. 1 and 4.) This spindle 2 is mounted in suitable bearings 4 and 5 carried by the lathe frame (not shown) and suitable pulleys P are mounted on said spindle between said bearings. As

shown the bearing 5 has a rearwardly pror jeoted externally threaded hub 6 for detachable connection with a collar 7 which is designed for connecting to said bearing 5 a cylindrical casing 8 constituting a part of this invention and which is removably se-.

cured to said collar by bolts 9.

A rod 10 is mounted in the spindle 2 and casing 8 and is connected at its front end with a shank 11 of a head 12 disposed in the hollow chuck head 1. (See Figs. 2, 3, and 4.) The head 12 as shown in Fig. 11 is provided with three pairs of laterally spaced parallel arms 13 between each pair of which is mounted a pair of laterally spaced rollers 14 for a purpose to be described.

The chuck herein shown is equipped on its front face with three radially movable jaws 15 (see Fig. 1). One of the jaws only is shown in the other figures to prevent confusion in illustration. These jaws 15 as shown are each constructed of two members 16 and 17 adjustably connected by a screw 18 which engages a threaded bore on the opposed face of the member 17 (see Figs. 1 and 4) and by means of which the outer or gripping portion 17 of the jaw may beadjusted relatively tothe member 16 to prop erly position the gripping faces of the jaw for clamping engagement with the article to be held when the jaws are projected. The member 16 of each jaw is provided with a rearwardly extending arm or casting 19 provided on its opposite sides with recesses 20 opening towardtheir rear and between the inner and outer walls of which are designed or rear end of said recesses being greater than that at the inner or front end thus forming quick acting and slow acting cam surfaces for the passage thereover of the rollers 14 in their forward movement which is caused by the projection of the head 12 by means to be described, it being obvious that when the rollers have passed the steeper inclination at the outer end of the recesses a slight movement only will be imparted to the jaws on the further projection of said rollers, thereby causing a more gradual closing of the jaws after the rollers pass the steepest parts of the inclinedwalls of the recesses 20, which parts are here shown formed about'midway the length of the recesses. v I

Loosely mounted'on the rod 10 within the casing 8 is a collar 21 which is clamped between a washer 22 keyed to said rod 10 and a'sleeve 23. The washer 22 is held in operative position byjam nuts 24 and 25 and the sleeve 23 by means of a coiled spring 26. A ball thrust bearing 27 is disposed between the collar 21 and the sleeve 23, said sleeve 23 being provided with a laterally extending annular flange 28 at its inner end. and between which flange and said collar 21 said ball bearing is mounted.

1K collar 29 is'fixed to the rod 10 at a point spaced from the collar 21 and the coiledspring 26 is disposed between this collar 29 and the sleeve 23 and is designed to be compressed therebetween 'when the rod is, moved forwardly beyond a predetermined point.

A bracket 30. projects laterally from the casing 8 and is preferably made integral therewith and is designed to support a lever 31 which is fulcrumed on said bracket and which comprises two diverging or outwardly extending arms 32 and 33 as shown in Fig. 9, said arms spanning the casing 8 and being connected with the collar 21 onthe rod 10 by means of links 34: and 35, said links'being connectedat one end with said lever arms and at their other ends with said collar 21 and'which are designed on the operation of the lever to project or retract the rod 10 as will be hereinafter more fully described.

A ratchet bar 36 extends laterally from the casing at the sideopposite the bracket 30 and is designed to be engaged by a pawl 37 carried by thelever 31 and mounted between the arms 32 and 33 thereof as is said handle 38 and are pivotally connectedat their free ends with the outer ends of said links 40.

A spring 41 is positioned between the pawl operating lever 39 and the handle 38 of the rod controlling lever and normally holds said lever 39 in open position with the pawl thereof disposed in the path of the opposite points with longitudinally extending slots 8 in which the studs or bolts 34. and 35 which connect the lin {S 34 and 35 with the collar 21 are designed to slide when the rod is'projected or retracted. by swinging the lever 31 in a forward or rearward direction as may be desired. An adjustable stop l2 is mounted on the bracket 30 and is disposed in the path of the lever 31 for limiting its extreme inward movement.

In the operation of this device the jaws 15 are first adjusted to adapt them to engage the article to be held, said adjustment being accomplished by means of the screws 18 above described and when the work or article to be clamped has been positioned between the jaws the parts being in the position shown in Fig. 2, the lever 31 is moved forwardly into the position shown in Fig. 3 which movement projects the rod 10 and with it the head 12 thereby forcing the rollers 1% into the cam recesses of the arms 19 thus causing the jaws to move radially inward into engagement with the article to be held as is shown in Fig. and when the parts are in this position the pawl 37 will be engaged with one of the teeth of the rack 36 and the rollers will be at the summit of the steeper or abrupt portions of the inclines of the recesses 20. A. further forward movement of the lever 31 will cause the collar 21 to slide forwardly on the rod 10 and the pawl to ride over the teeth of the ratchet bar 30 and thus compress the spring 26 between the sleeve 23 and collar 29 as shown in Fig. l and when the parts are so I disposed the article to be held will be securely clamped between the jaws 15 of the chuck and the pawl 37 will be engaged with another of the teeth of the rack 36 nearer the inner end of said rack. lVhen the parts are in this position should the article clamped crumble or slip as may occur with rough castings, or the jaws l5 slip or in any other way become loosened in their clamping engagement with the work or article to be held the spring 26 will. automatically force the rod 10 forward and thereby renew the gripping action of the jaws on the work and thus securely hold it in operative position. This spring 26 when the parts are in the position shown in Fig. 4 serves also to cushion the gripping action of the jaws and prevents them from crushing or otherwise injuring the parts clamped between them, and yet permits them to securely hold said article to provide for its turning with the chuck.

Immediately upon the release of the pawl 87 from the rack 36 the spring 26 will expand and thereby automatically retract the collar 21 and thus disengage the jaws from the work which is effected by means of the rollers passing'outward in the cam slots of the arms 19. From the above it will be obvious that this spring 26 performs the dollble function of cushioning means for the jaws and means for automatically renewing the grip of the jaws should they for any reason become loosened on the work when the parts are in normal clamping position as shown in Fig. 4.

From the above description it will be obvious that this attachment may be readily applied'to any lathe chuck by connecting the casing 8 thereof with the spindle 2 and connecting the rod 10 with the gripping jaws,

whereby the projection of the rod will operate to close the jaws and the retraction thereof to open them.

I claim as my invention:

7 1. In a chuck the combination of a hollow chuck head having radially movable jaws therein provided with rearwardly extending longitudinally disposed arms having quick and slow acting cam faces, the slow acting faces being disposed in advance of the quick acting faces, a jaw operating head mounted to reciprocate in said chuck head in a plane at right angles to the plane of movement of said jaws and having elements engaging the cam faces of said arms, a rod extending rearwardly from said jaw operating head, a fixed and a movable stop on, said rod, a coiled spring on said rod between said stops, a lever connected with said movable stop to move said rod, stop, spring and jaw operating head as a single unit during the engagement of the elements of said jaw operating head with the quick acting cam faces of said jaw arms, and to compress said spring after the engagement of said elements with the slow acting cam faces of the jaw arms, and means for locking said lever in adjusted position.

2. In a chuck, the combination of a hollow chuck head having radially movable jaws therein, said jaws having rearwardly extending arms, each provided with longitudinally extending rearwardly opening angular recesses, the inner and outer walls of said recesses being inclined forwardly and outwardly to form cam faces, the inclination of the rear ends of said walls being more abrupt than that of their inner ends to form quick and slow acting cam faces, amember mounted to reciprocate in said head in a direction at right angles to the direction of movement of said jaws and parallel with the plane occupied by said jaw arms, said memher having pairs of parallel laterally spaced arms, rollers extending from the opposed inner faces of said arms and positioned to enter the recesses in the jaw arms, one of the jaw arms extending between each pair of rollers, the diameter of said rollers bein substantially the same as the width of said recesses, and means for reciprocating said roller carrying member to open and close the jaws.

3. The combination with a chuck head having work clamping jaws and a hollow drivin spindle, a member mounted in said head for operating said jaws, supporting means for said spindle having a hub alined with the spindle, of a casing detachably connected with said hub and having opposed longitudinally extending slots in its side walls, a bracket mounted on said casing in a plane between said slots, a ratchet bar on said casing at a point diametrically opposite said bracket, an actuating rod connected with said jaw operating member and extending through said spindle and hub into said casing, a stop on said rod within said casing, a collar mounted to slide on said rod in said casing, a coiled spring mounted on said rod between said stop and collar, trunnions extending radially from said collar through the slots in said casing, a lever fulcrumed on said bracket and having diverging arms spanning said casing, links pivotally connected at one end with said trunnions and at their other ends with said lever arms interniediately of the length of said arms, the free ends of said lever arms converging and merging into a handle, a pawl mounted at the converging ends of said lever arms and positioned to engage the ratchet bar of said casing, and a pawl controlling lever carried by said handle, said first mentioned lever being operable to reciprocate the chuck jaw operating rod for opening and closing the aws.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

' ALBERT E. CHURCH.

Witnesses:

H. E. MYERS, W. H. RYBECK.

Copies of this patent may be obtained for five cents each, by addressing the Gommlssioner or Patenta,

, Washington, D. 0. 

